Age important in hereditary pancreatic cancer risk

NEW YORK (Reuters Health) - For people with a strong family history of pancreatic cancer, having a relative who was diagnosed before the age of 50 may further raise the risk of developing the deadly disease, a new study finds.

About 3 percent of all cases of pancreatic cancer are what's known as familial pancreatic cancer, where the disease has affected two or more first-degree relatives -- siblings or a parent and child. Researchers have found mutations in several genes that seem to be associated with the cancer.

In the new study, investigators found that among these families, the age at which affected relatives were diagnosed was an important factor in other family members' risk of developing the cancer.

Compared with the general population, people in families affected by familial pancreatic cancer had a six-fold higher risk of developing the disease.

But the risk was increased nine-fold when a family member had been diagnosed with the disease before the age of 50, the researchers report in the Journal of the National Cancer Institute.

The findings should help in counseling people at high genetic risk of pancreatic cancer -- giving a clearer picture of an individual's likelihood of developing the disease, said researcher Dr. Alison P. Klein, of Johns Hopkins School of Medicine in Baltimore.

The results may also help researchers figure out which individuals might benefit most from pancreatic cancer screening to detect suspicious growths early.

Pancreatic cancer has a dismal prognosis, with only about 5 percent of patients still alive five years after diagnosis.

This is largely because the cancer is rarely caught early; its symptoms, which include weight loss, pain in the upper abdomen and jaundice, usually arise only after the cancer has spread.

As it stands, however, people from families affected by hereditary pancreatic cancer are not routinely screened. Researchers are still trying to determine which tests can reliably detect early cancer in people without symptoms, and which individuals within these families are at particular risk.

"Right now, there's no well-established screening program," Klein told Reuters Health. She and her colleagues at Hopkins are currently studying the effectiveness of endoscopic ultrasound, where an ultrasound probe is passed through the mouth and threaded down into the small intestine, where it is aimed at the pancreas.

The current findings, the researchers say, suggest that clinical trials should focus on families with young-onset pancreatic cancer.

The study included more than 9,000 individuals from 1,718 families enrolled in a pancreatic cancer registry begun in 1994. Some families had a history of familial pancreatic cancer, while others had a history of "sporadic" pancreatic cancer -- where the disease had not affected a pair of first-degree relatives.

Overall, 29 people from familial pancreatic cancer families developed the cancer after entering the study, as did 8 people from families with sporadic pancreatic cancer.

Klein's team found that a family history of early-onset cancer did not seem to alter the risk of people in families with sporadic cancer, but it was important when it came to familial pancreatic cancer.

They estimate, for example, that for a family member with one or two first-degree relatives with pancreatic cancer, and at least one relative whose disease was diagnosed at age 40, the odds of developing pancreatic cancer by age 80 are about 16 percent.

Those odds dropped to 7 percent, however, if relatives had been diagnosed no earlier than age 60 and to 3 percent if the cutoff were age 80.

The average American, Klein noted, has about a 1 percent chance of developing pancreatic cancer in his or her lifetime.

SOURCE: Journal of the National Cancer Institute, online January 12, 2010.